Strange Idle - after fuel pump swap (E85)
 

Ok - so I’m coming to the experts for this one.

Here's the ISSUE: https://www.youtube.com/watch?v=XC_BoHgy2jA (not sure how to embed the video, have tried youtube / youtube hd in brackets)

Watch the first 35 seconds.


2016 370z Nismo
Z1 Cold Air Intake
FI Test Pipes
Greddy GT Exhaust

AEM’s 340LPH E85 Fuel Pump (runs strictly E85)
1050cc Injectors
Tuned by Seb (V5 Ecutek)

The Issue: For the first 5 - 10 minutes, my AFR and IDLE will be a bit wonky, as in, my AFR is pretty steady at 14.7 - Driving is normal - feels fine, BUT at idle - my AFR goes anywhere from 13-15.5 and my RPM goes from 700 (once hit 675) up to 950 and goes back and forth. This ONLY happens once or twice during the first 5-10 minutes of driving. This is cold or not, so I could drive the car for 30 minutes. Shut it off, turn it back on 15 minutes and it will happen again.

After the 5-10 minutes my idle is perfect.

What I’ve done:

Retuned with Seb
Battery Check - Completely normal.
Cleaned manifolds and throttle bodies.

Talked to the dealership and my performance shop. Dealership says everything is good. Seb says if there’s an issue (which he can’t see one) maybe it’s the WB O2 sensors.

My next step would be maybe a vacuum leak check?


Do you guys have any idea what I should look at or is this just the nature of a Z with E85 and my mods?


Thanks guys.

Have you tried the idle relearn procedure? There's a feature that should allow you to do this on the phone app or proECU (i think)


Edit: I'll give my car a cold start. I have ID1050x injectors, but i'm on the standard fuel pump. other than the slow ish cold start, i havent had any issues that i noticed once it was actually running

Here's a quick video. I had to pull it out of the garage, but it wasn't doing anything too crazy.

I should note that I do have brand new widebands (a product of troubleshooting something else) so I am not 100% sure if this helps. I'm by no means an expert, but maybe it has to do with the startup/cat-warmup procedure? I'm just throwing out theories.

Yeah I’ve done the idle relearn through ECUTEK and the dealer said they’ve done it as well (like the video you showed).

Also I should say - I’ve got a fuel gauge on my car and fuel psi is right around 56-58. Seb says that’s perfect.

Thanks.

I wonder if I should just put new WB O2s in and see if that takes care of it.

Also I should say there’s is 0 performance loss - just this annoying idle dip once or twice during first 10 mins of driving.

So on a cold start. Mine does pretty much the same thing. But I don’t actually see any idle dip until I drive it for a few minutes.

Almost like once it gets gas - it has to relearn idle. Does that make sense?

I didn’t do the idle learn procedure in the video. I just did a cold start. If your car behaves the same way when cold, I think that’s normal man. I think if you posted a video of what’s happening it would help.

Yeah I will do that tomorrow.

Good idea.

That's just the nature. Have same setup with same issues. Once your 100% 85 it will somewhat go away .seems like the computer is trying to read the content as its coming in.my car takes a bit longer to start once the engine is warm as well

So I’ve been running e85 for almost a year now, but my fuel pump is 2 months old.
I’m at 75% ethanol content.

Been retuned and everything.

You think it’s just the nature of the Z on e85?

Use smaller injectors?

Ok so I caught a smaller dip this morning - it tends to happen like this - and only a few times during the first 5 - 10 minutes of driving..

This just normal? It’s at just about 10 seconds - 15 seconds — something like that… It dips down to 700 and boosts up to 900


https://youtu.be/GzlKLDryw68

I dont know to be honest. that could be your a/c compressor turning on or off, or it could be something else.

What is the injector dwell time when wfo?